Lessons from the Dengue Vaccine Trial

What we can learn from a five-year placebo-controlled trial

In Chapter 10 of my book, Vaccines, Amen, I do a deep dive into vaccine clinical trials—the ones the FDA relies upon to license each vaccine. As you’ve heard me repeat many times before, no routine childhood vaccine was licensed based on a long-term placebo-controlled trial. But there is one non-routine vaccine that did have a proper trial:

To further bring this issue into focus, there is one vaccine on the CDC childhood schedule that was licensed based on a long-term placebo-controlled trial. That is Sanofi’s vaccine for dengue. This vaccine is only recommended by CDC for children in endemic dengue areas, and dengue is not endemic in the United States.

This vaccine’s trial had a placebo-controlled group and reviewed safety for five years. Again: five years of safety review with a placebo control. After the third year of the trial, researchers learned that children under 6 years old had an increased risk of severe harm and death from this vaccine. This harm would never have been uncovered by the short trials with no placebo control which occur for the routine vaccines on CDC’s childhood schedule.

Researchers also found that children older than six who had never had dengue and received this vaccine likewise had a serious increased risk of severe harm and death. Because of these findings, which took years in a placebo-controlled trial to uncover, this vaccine is only given to older children and to only those who have previously had dengue. As disclosed by the FDA and Sanofi: “Those not previously infected are at increased risk for severe dengue disease when vaccinated and subsequently infected with dengue virus.”

If each routine childhood vaccine on the CDC schedule was licensed based on a robust clinical trial with a placebo control (or another vaccine as the control licensed based on this standard) and five years of safety review, widespread harm to infants and children could have been avoided. Just think about the DTP vaccine studies and the high rate of serious adverse events in many of these trials that are simply written off because there was no placebo control group to compare against and the safety review is otherwise too short.

Vaccines, Amen is available on Amazon.